The present invention relates to crop harvesting implements having pickup attachments for lifting windrows of crop materials to crop processing elements of the implements and more particularly relates to the teeth of such pickups as are used for conveying crop to the baling chamber of an "open throat" large round baler, i.e., one that does not use any compression rolls through which crop passes on its way to the baling chamber.
The feeding of crop into round balers of "open throat" design during the initiation of bale formation has long posed a problem. This is because these open throat balers rely on the growing or forming bale in the baling chamber to help feed the crop into the baler. Thus, until the bale starts to roll, the feeding of crop to the baling chamber comes almost totally from the pickup device. This requires extra care by the operator to avoid plugging the baler during the first few feet of forward travel. It is particularly important to be careful to avoid getting crops caught at or near the ends of the pickup device, because part of the windrow occasionally extends beyond the end of the pickup. This creates an extra volume of crop to be fed into the baler at the ends of the pickup. Unfortunately, it is fairly common for this situation to occur during bale starting because, in the typical case, the operator of the tractor pulling the baler has backed up the baler to discharge a just-completed bale and upon driving forward after such discharge approaches the windrow at an angle. Just as typically, in order to form a bale having a good shape, an operator will intentionally drive the tractor in a weaving pattern so that the trailing baler moves back and forth relative to the windrow for the purpose of adding more crop to an end of the bale which is smaller than the other end. After discharge of such a bale, the baler may still be positioned for feeding crop at that end of the pickup where feeding was taking place when the previous bale was finished.
Another factor which contributes to difficult bale starting is the orientation or stiffness of crop stems, as well as the slipperiness of crop against the bale-forming belts. This is so because, if the incoming crop is difficult to flex or grip compared to normal crops, it is relatively difficult to have the crop begin rolling up on itself. This would be analogous, for example, to the relative ease of rolling up a flexible carpet or sleeping bag as opposed to rolling up a stiffer bed mattress or a slippery, stiff sheet of plastic.